The above referenced issued U.S. Pat. No. 5,736,897 shows a state-variable filter used as a Pre-Amplifier that receives an input program signal and processes the input program signal to provide three band-pass signals comprising a low band-pass signal (LFRCMIPS), a mid-range band pass signal (MFRCMIPS) and a high band-pass signal (HFRCMIPS) to respective inputs of a summing amplifier. The three signal components are then summed and output as a compensated signal at its output. The ‘897’ Patent then shows the compensated signal being processed by a “Compander” Circuit first introduced in the above referenced U.S. Pat. No. 5,510,752. Application Ser. No. 09/444,541 referenced above shows the compensated signal at the output of the state-variable filter driving an audio boost circuit.
The compensated signal is free of harmonic distortion in each of the above mentioned topologies. A determination has been made that some applications benefit from the introduction of a predetermined amount of harmonic distortion into the compensated signal out of the pre amplifier. This application provides an initial input amplifier that receives the program signal and provides a buffered program signal. The buffered program signal is sampled by a Harmonic Generator circuit. The Harmonic Generator circuit then generates a family of harmonic signals that are summed with the buffered program signal for cumulative processing by the state variable filter to provide a composite compensated signal having a predetermined component of harmonics.